Just some background if what you're looking to do by contacting the GM is to lodge a complaint.

I used to stay at the Westin Grand and the Westin Embassy Row at least once a month. Have never heard so many people complain about the service at these hotels, especially given that they're Westins. I don't think I ever lodged a complaint, but I'm sure there's no shortage of them. I imagine they are pretty thick skinned at this point.